Mannitol Fermentation Test Research Articles

METHICILLINE RESISTANT STATUS OF COAGULASE NEGATIVE STAPHYLOCOCCUS ISOLATED FROM BOVINE MASTITIS

Mastitis continues to be a major economic issue for dairy producers all over the world. A total of 100 milk samples from mastitic buffaloes and cows were subjected to bacteriological examination in the department of Veterinary Microbiology for the isolation of methicillin-resistant Staphylococcus aureus. 68 staphylococci spp. were isolated on the basis of colony morphology, haemolytic pattern on blood agar plates and growth on mannitol salt agar plates. Gram’s staining; catalase test, clumping factor test, coagulase test and mannitol fermentation tests were performed for the confirmation of Staphylococcus aureus and Staphylococcus epidermidis. 52 Staphylococcus aureus and 16 Staphylococcus epidermidis were purified on mannitol salt agar slants. Nitrocefin disks (Fluka) were used for the detection of beta-lactamase activity of these staphylococci. Out of 52 spp. of Staphylococcus aureus, 16 (30.76%) were found positive for beta-lactamase production; similarly, out of 16 spp. of Staphylococcus epidermidis 4 (25%) were found positive for beta-lactamase production. 29.41% of isolated staphylococci were found positive for beta-lactamase production through nitrocefin test. This beta-lactamase producer was subjected to antimicrobial susceptibility testing through disk diffusion test using oxacillin 1μg and cefoxitin 10μg antibiotic disks. Twenty two 22 (32.35%) isolates of staphylococci from a total of 68 were resistant to these disks hence declared as methicillin-resistant staphylococci. These methicillin-resistant staphylococci were subjected to antibiotic sensitivity testing through disc diffusion test using enrofloxacin, norfloxacin, chloramphenicol and amoxycillin discs. The results of in vitro sensitivity tests showed that enrofloxacin was most effective followed by norfloxacin and chloramphenicol. Amoxycillin was found ineffective. The aspect of methicillin-resistantce should be kept in mind for the treatment of staphylococcal mastitis.

Asymptomatic nasopharyngeal bacterial carriage, multi-drug resistance pattern and associated factors among primary school children at Debre Berhan town, North Shewa, Ethiopia

BackgroundNasopharyngeal carriage of bacteria is the main source for transmission of pathogens across individuals and horizontal spread of organisms in the community. It is an important risk factor for the acquisition of community-acquired respiratory tract infection. It is the major public health problem among children. The asymptomatic carriage of nasopharyngeal bacteria is different globally, particularly in Africa, carriage is higher in children and decreases with increasing age, 63.2% in children less than 5 years, 42.6% in children 5–15 years, and 28.0% in adults older than 15 years.ObjectiveThe aims of this study was to determine asymptomatic nasopharyngeal bacterial carriage, multi-drug resistance pattern and associated factors among primary school children at Debre Berhan town, North Shewa, Ethiopia.MethodsInstitutional based cross-sectional study was conducted at Debre Berhan town primary schools from February 1 to April 30, 2021. Primarily, the schools were stratified into two strata, public and private primary schools. From a total of sixteen government and fourteen private primary schools, five government and five private schools were selected by using a simple random sampling technique. Socio-demographic variables and potential risk factors were assessed using a structured questionnaire. A total of 384 nasopharyngeal swab samples were collected using sterile swabs aseptically; and inoculated on Blood agar, Chocolate agar, MacConkey agar, and Mannitol salt agar. The colony was characterized to isolate bacteria, and bacterial identification was performed by Gram reaction, hemolysis patterns, colonial characteristics and pigmentation, catalase test, coagulase test, mannitol fermentation test, oxidase test, fermentation of carbohydrates, H2S production, motility, formation of indole, triple sugar iron agar (TSI), citrate utilization, lysine decarboxylase or methyl red vogues proskur utilization, urea hydrolysis and satellitism tests. Antimicrobial sensitivity tests were performed by using modified Kirby-Bauer disk diffusion method. Data were entered into statistical package Epi data 4.0.0.6 and transferred to and analyzed using SPSS software version-23. P value of < 0.05 with Odds ratio (OR) and 95% confidence interval (CIs) was considered as statistically significant.ResultsThe overall prevalence of nasopharyngeal carriage of bacterial isolate was 35.7% (95% CI 30.7–40.7%). The predominant isolates were Staphylococcus aureus 54.5% followed by coagulase-negative Staphylococcus 35.8%, and Streptococcus pyogens 4.5%. Most bacterial isolates were susceptible to chloramphenicol, ciprofloxacin, gentamycin, nitrofurantoin, azithromycin, ciprofloxacin; and the overall multidrug resistance pattern of isolated bacteria was 62.03% out of 137 bacterial isolates. Numbers of rooms ≤ 2 per house [AOR = 5.88, 95%CI 1.26–27.57], having history of hospitalization [AOR = 4.08, 95%CI 1.45–11.53], passive smoking [AOR = 4.87, 95%CI 1.49–15.97], family size of > 5 members [AOR = 2.17, 95%CI 1.24–3.81], and number of students in the classroom [AOR = 2.35,95%CI 1.37–4.02] were statistically significant associated risk factors for nasopharyngeal bacteria carriage.ConclusionAsymptomatic nasopharyngeal bacteria carriage in children is alarming for community-acquired infection. The overall multidrug resistance was very high. The risk of the carriage was increased with having a history of passive smoking, being in large family size and number of students per class. Longitudinal follow-up studies would be helpful for better understanding the infection risk in bacterial pathogen carriers.

Antibacterial Activity of Cinnamomum Zeylanicum Essential Oil Against Methicillin-resistant Staphylococcus Aureus Strains Isolated From Skin Lesions In Patients With Psoriasis

Background and Objectives: Psoriasis is a chronic and inflammatory skin disease, which is has no definitive cure. Several microbial agents have been identified that have a role in the exacerbation of psoriasis, one of which is Staphylococcus aureus. Increased Methicillin-resistance Staphylococcus aureus (MRSA) strains is a major problem worldwide. This study aims to evaluate the antibacterial effect of Cinnamomum zeylanicum essential oil on MRSA strains isolated from skin lesions in patients with psoriasis. Methods: In this study, participants were 140 patients with psoriasis referred to the dermatology and rheumatology clinic of Shariati Hospital in Tehran, Iran. Diagnostic tests including gram staining, catalase test, tube coagulase test, mannitol fermentation test, and deoxyribonuclease test were performed. To identify the phenotype of MRSA strains, methicillin susceptibility testing was performed using cefoxitin by disk diffusion method. The antimicrobial activity of Cinnamomum zeylanicum essential oil was investigated by broth microdilution method and its minimum inhibitory concentration against MRSA strains was calculated. Results: Of 140 patients, 43.57% had infection with Staphylococcus aureus and 14.28% had MRSA infection. There was no significant relationship between gender, age and sampling area in patients with MRSA infection. The results showed that Cinnamomum zeylanicum essential oil had antimicrobial effects on MRSA strains. Conclusion: The Cinnamomum zeylanicum essential oil can be a suitable alternative to antibiotics for the control and treatment of skin infections caused by Staphylococcus aureus.

Preliminary study for investigation of G. anatis in broilers Abdelazeem M. Algammal1, Wafaa A. Abd El-Ghany2, Amira A. Elewa3, and Ahmed M. Hamouda3

Gallibacterium anatis is recognized as a globally distributed species of bacteria that has been isolated from birds . The aim of the present prelaminary study is to investigate the prevalence of G. anatis isolated from diseased chickens from private commercial broiler farms at Ismailia governorate, Egypt. A total of 80 tracheal swabs obtained from broiler chickens suffering from respiratory manifestations. The collected specimens were subjected to bacteriological examination and the prevalence of G.anatis was 35%. All obtained isolates were positive for oxidase, catalase, nitrate reduction, sucrose, sorbitol, and mannitol fermentation tests. However, the obtained isolates were negative for citrate utilization, indole, urease, gelatinase and maltose fermentation tests. Besides, the recovered isolates were negative for the motility test. The gold standard method of bacterial isolation and identification( including culture characters, hemolytic activity on blood agar, morphological characters, motility test, and biochemical characteristics) is essential for characterization of G. anatis in birds.

Identifikasi Staphylococcus aureus Pada Abon Sapi Di Pasar Pahing Kota Kediri

Contamination of processed beef foods such as abon can be caused by various types of microbes, one of which is Staphylococcus aureus. Staphylococcus aureus can cause various infections, both on the skin, gastrointestinal tract, or endocarditis. The objective of this research was to determine the presence of Staphylococcus aureus in beef abon sold in Pahing Market, Kediri. Abon used is non-branded beef abon which is as many as 10 samples obtained by total sampling technique. Samples were tested by observation of colony morphology through Gram staining, mannitol fermentation test, catalase and coagulase test, and acetoin test. The samples were inoculated on Broth NaCl (ink. 24 hour-37°C), then inoculated on MSA (ink. 24 hour-37°C), and VP (ink. 2x24 hours-37°C). Catalase and coagulase tests were carried out by taking colonies on MSA media. The results showed that there were 9 abon samples contaminated with Staphylococcus aureus as indicated by Gram positive staining results, positive (perfect) mannitol fermentation, and positive acetoin, catalase, and coagulase test. The causes of contamination are contaminated abon ingredients, the manufacturing process using less sterile tools, poor handling and processing, processing food with dirty hands, food stored without cover, sick food processors, and dirty markets

Antibiotic Susceptibility Pattern of Staphylococcus aureus Isolated from Clinical Samples in Specialist Hospital, Sokoto

Aim: The study was to determine the antibiotic susceptibility pattern of Staphylococcus aureus isolates against some conventional antibiotics.&#x0D; Study Design: Hospital based cross-sectional study.&#x0D; Place and Duration of Study: The study was conducted in Specialist Hospital, Sokoto Metropolis, Sokoto State Nigeria, between June 2018 and September 2018.&#x0D; Methodology: One hundred (100) Staphylococcus aureus isolates were used in this study. Gram’s staining, catalase, coagulase and mannitol fermentation tests were used to identify and confirm the isolates. Antibiotic susceptibility testing was carried out by disc agar diffusion test.&#x0D; Results: In the present study 63.0% of the Staphylococcus aureus isolates were from male subjects, while 37.0% were from female subjects. The age group with the highest number of isolates was 11-20 years (37%) and the least (9%) was seen in 41-50 years. Subjects with urine samples had the highest frequency of Staphylococcus aureus isolates with 32.0% and those with high vaginal swab had the lowest 6.0%. The antibiotics susceptibility testing showed that 40% of Staphylococcus aureus isolates were susceptible to Clindamycin, 64% to Ciprofloxacin, 57% to Erythromycin, 71% to Gentamicin, 34% to Cefoxitin, 46% to Quinupristin/Dalfopristin, 58% to Tetracycline and Sulphamethaxazole –Trimethoprim respectively. Screening for MRSA was carried out by antibiotic sensitivity testing using cefoxitin and a prevalence of 66% was obtained. This study showed that Gentamicin and Ciprofloxacin were the most active antibiotics against Staphylococcus aureus.&#x0D; Conclusion: There is the need for consistent on-going antimicrobial resistance surveillance for important and commonly isolated clinically significant pathogens of staphylococcal species to form the basis for developing and implementing measures that can reduce the burden of antimicrobial resistance and prevent a probable impending public health problem.

The Incidence of Methicillin Resistance Staphylococcus aureus in Diabetic Septic Foot

Background: Foot infection is the most common problem in a person with diabetes. Infection in these patients is difficult to treat because these individuals have impaired microvascular supply, Which limits the access of phagocytic cell in the infected area and result in poor concentration of antibody in the infected tissue. Staphylococcus aureus is a major cause of potentially life-threatening infection which was acquired in the health care and community setting. These microorganisms have developed resistance against most classes of antibacterial agent as indicated by a dramatic increase in the number of healthcare-associated infection due to methicillin resistance S. aureus, which become endemic in hospitals worldwide. Methods: All collected samples were cultured directly on the blood and chocolate agar to primary isolation, then purified by several subcultures from a single well-isolated colony. Identification of isolated bacteria depends on gram reactions, organism morphology, colonial morphology in different media and biochemical tests-catalase test, coagulase test, DNase test, mannitol fermentation test, and VP test. The antimicrobial test was carried by disc diffusion method Kirby-Bauer method on Muller and Hinton media to several single antibiotic discs-Vancomycin, cloxacillin, Tobracillin, Ciprofloxacin, and Ceftriaxone. The inhibition zone was measured by ruler in millimeter the compared with incorporated chart. Results: A total of 50 diabetic patients with wound infection were including S. aureus n:20, 40% and other pathogens n:30,60%. Frequency of male was 43,86% while 7,14% were female. All patient were classified into two groups of age, one (35-55) with moderate frequency n:20, 40% and another age group (56-90) with the highest frequency n:30,60%. All isolated S. aureus were resisted cloxacillin while sensitive to vancomycin, 60% of them resist tobracillin 40% were sensitive and 10% resist ciprofloxacin 90% were sensitive, 25% were resisted ceftriaxone 75% were sensitive. Conclusion: MRSA is highly 40% prevalent among populations of S. aureus isolated from surgical site infection in Khartoum state. This study discusses the link between MRSA acquisition factors like age, sex, occupation, ethnicity, geographical location, hospitalization, antibiotic use, surgery and distinction community-acquired MRSA and hospital-acquired MRSA.

Nasal carriage of Staphylococcus aureus among indigenous people of Toba Qom ethnic, Benjamín Aceval, Paraguay

Background: Staphylococcus aureus are Gram positive cocci components of the normal microbiota of the skin and mucosa, but can attack other sites of the organism depending on favourable conditions. The condition of host of this bacterium colonizing the nasal mucosa is recognized as a potential risk factor for subsequent invasive infections. This research had the objective to investigate the prevalence of nasal carriers of S. aureus among Toba Qom indigenous ethnic group of the San Francisco de Asis community, Paraguay, and to determine the sensitivity profile to antimicrobial agents.Methods: 141 samples of the nasal cavities were analyzed. Isolation and identification were performed by conventional microbiological methods, by the staining characteristics of the Gram method, catalase and coagulase tests, mannitol fermentation test and deoxyribonuclease test. Antimicrobial susceptibility test was performed by the agar diffusion technique according to a procedure standardized by the National Committee for Clinical Laboratory Standards.Results: 22 of the 141 individual examined samples were colonized by Staphylococcus aureus, which corresponds to a prevalence of 15.6%.Conclusions: Multidrug-resistant strains were not isolated. All samples presented good sensitivity to most antibiotics except for nalidixic acid, which all samples presented resistance.

Screening method for Staphylococcus aureus identification in subclinical bovine mastitis from dairy farms.

Background:Staphylococcus aureus is one of the most important contagious bacteria causing subclinical bovine mastitis. This bacterial infection is commonly identified by determine the pathogen in bovine milk samples through conventional technique including coagulase test. However, this test has several disadvantages as low sensitivity, risk of biohazard, cost expensive, and limited preparation especially in local area.Aim:Aim of this study was to compare and assess the screening method, Mannitol fermentation test (Mannitol salt agar [MSA]), and deoxyribonuclease (DNase) test, for S. aureus identification in milk samples.Materials and Methods:A total of 224 subclinical bovine mastitis milk samples were collected from four provinces of Thailand and determined S. aureus using conventional method and also subjected to the screening test, MSA and DNase test. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) among both tests were analyzed and compared to the tube coagulase test (TCT), as reference method. Immunological test by latex agglutination and molecular assay by determined spa gene were also used to identify and differentiate S. aureus.Results:A total of 130 staphylococci were isolated by selective media, Gram-stain, and catalase test. The number of S. aureus which identified using TCT, MSA and DNase test were 32, 102, and 74 isolates, respectively. All TCT results were correlated to results of latex agglutination and spa gene which were 32 S. aureus. MSA showed 100% sensitivity, 28.57% specificity, 31.37% PPV, and 100% NPV, whereas DNase showed 53.13% sensitivity, 41.84% specificity, 22.97% PPV, and 73.21% NPV. DNase test showed higher specificity value than MSA but the test presented 26.79% false negative results whereas no false-negative result from MSA when comparing to TCT.Conclusion:MSA had a tendency to be a good preference for screening S. aureus because of its high sensitivity and NPV. The result from this study will improve a choice to use a screening test to diagnose S. aureus of veterinary field for prompt disease controlling and effective treatment.

Microbiological Quality of Cattle Milk Obtained from Dairy Farms around Quetta Valley

Milk is significant sources of protein and other nutrients but can be infected by pathogenic agents. Milk itself possesses small number of micro-organism when it leaves the normal udder however, it may get contaminated from manure, water, soil, milker’s hands, utensil and flies. In milk the microbial load is a major factor to determining its quality, which shows the cleanliness of the milking tools, condition of storage, manner of transport as well as the cleanliness of the udder of the individual animal. The aim of this study was to examine the microbiological quality of cattle milk. The milk samples were collected from dairy farms existed in and around Quetta Balochistan. The result showed that the microbial quality of milk obtained from dairy farmer was very low due to the isolation of E. coli and Staphylococcus aureus. The E. coli and Staphylococcus aureus were confirmed by Indole, Methyl Red, Vogues Proskeur, Citrate, Nitrate Production, Cagulase and Mannitol Fermentation tests.

Comparison of Phenotypic and Genotypic Identification Methods of Pasteurella multocida Serotypes Isolated from Pigs

Background: Pasteurella multocida serotypes A and D are commonly associated with pneumonia and pleuritis in pigs. Different phenotypic techniques, such as hyaluronidase and acriflavine tests, and genotyping techniques, such as PCR, are used to distinguish between these serotypes. The objective of this study was to compare the capsular identification methods of type A and type D P. multocida isolated from pigs using both phenotypic (hyaluronidase and acriflavine tests) and genotypic (multiplex PCR) techniques.Materials, Methods &amp; Results: A total of 44 lyophilized P. multocida isolates, obtained between 1981 and 1997 from pig farms at Rio Grande do Sul State, Brazil, were analyzed. The isolates were reactivated in Brain Heart Infusion (BHI) broth and cultured in BHI broth and blood agar supplemented with 5% sheep blood. Colony identity was further confirmed by evaluating colony morphology in blood agar and confirming the absence of growth on MacConkey agar. Bacteria in Tryptone Soy Agar (TSA) were used for the Triple Sugar Iron (TSI), Sulfide-Indole-Motility (SIM), and nitrate, glucose, lactose, sucrose and mannitol fermentation tests. For hyaluronidase test, P. multocida colonies were streaked transversally across the entire plate, approximately 3-5mm apart, in order to observe their lines of growth. Following this, a hyaluronidase producing strain of Staphylococcus aureus was heavily streaked at right angles to the P. multocida lines and the plates were incubated at 37°C for 24 h. Type A isolates were then identified as those with smaller colonies in the region adjacent to the Staphylococcus aureus streak (negative satellitism). For acriflavine test, the isolates were inoculated into tubes containing 2 mL of BHI, incubated at 37°C for 18-24 h, centrifuged (500 g for 15 min) and 1.5 mL of the supernatant was discarded. A 1:1000 solution of acriflavine neutral (0.5 mL) was then added to the residual broth containing bacteria and kept at room temperature. Solutions of acriflavine were freshly prepared each week and stored protected from light. Type D strains were identified by the appearance of a heavy flocculent precipitate within 5 min. DNA extraction by heat shock was performed prior to multiplex PCR for the detection of capsular genes hyaD-hyaC (capsular typing A) and dcbF (capsular typing D). Test of symmetry and a weighted kappa coefficient were used to evaluate correlations and to assess agreement of the results between the identification methods, respectively. Phenotypic tests showed that two isolates were type D (4.55%), 40 were type A (90.9%) and two (4.55%) were untypable isolates (4.55%) while PCR showed that 38 isolates were type A (86.36%) and six were type D (13.64%). The correlation analysis between the phenotypic and genotypic tests showed that 90.9% of the strains were identified as belonging to the same serotype by both tests and the weighted kappa coefficient (K = 0.633) indicates a substantial agreement between the two tests.Discussion: There was a disagreement between the phenotypic and genotypic results in four of the isolates (9.09%). The phenotypically untypable isolates were classified as type D by multiplex PCR. Nonetheless, we conclude that PCR testing is a more reliable method to differentiate between P. multocida serotypes A and D.

Occurrence of Enterotoxigenic S. aureus in Half-Cooked Chicken Products.

Sixty samples of half- cooked chicken (chicken wings, chicken drumsticks and chicken pane) (20 each) were collected from Menofia governorate and were examined for the incidence of Staphylococcus aureusand their enterotoxins. The percentage of positive samples for S.aureus was 40%, 40% and 25% with mean count0.4X10­2 ±0.15X10­2 , 0.28X102 ±0.2X 102 and 0.19X102 ±0.2X102 for chicken wings, chicken drumsticks and chicken panes, respectively.. All isolated strains of S.aureusshowed positive Catalase, Coagulase and Mannitol Fermentation test and 100% of isolates had hemolytic activity on sheep blood agar and 9.52% had hemolytic activity on human blood agar. The incidence of enterotoxin A produced by S.aureuswas 50% and 37.5% in chicken wings and chicken drumsticks, respectively.

Prevalence of Methicillin-Resistant and Methicillin-Susceptible S. Aureusin the Saliva of Health Professionals

INTRODUCTION:S. aureus is one of the main agents of nosocomial infection and is sometimes difficult to treat with currently available active antimicrobials.PURPOSE:To analyze the prevalence of methicillin-susceptible S.aureus (MSSA) and methicillin-resistant S. aureus (MRSA) as well as the MRSA antimicrobial susceptibility profile isolated in the saliva of health professionals at a large public education hospital.MATERIALS AND METHODS:The project was approved by the research and ethics committee of the institution under study. Three samples of saliva from 340 health professionals were collected. The saliva analysis used to identify S. aureus was based on mannitol fermentation tests, catalase production, coagulase, DNAse, and lecithinase. In order to detect MRSA, samples were submitted to the disk diffusion test and the oxacillin agar screening test. In order to identify the minimum inhibitory concentration, the Etest® technique was used.RESULTS:The prevalence of MSSA was 43.5% (148/340), and MRSA was 4.1% (14/340). MRSA detected by the diffusion disk test, was 100% resistant to penicillin and oxacillin, 92.9% resistant to erythromycin, 57.1% resistant to clindamycin, 42.9% resistant to ciprofloxacin and 57.1% resistant to cefoxetin.CONCLUSION:This subject is important for both the education of health professionals and for preventative measures. Standard and contact-precautions should be employed in professional practice.

Prevalence of Staphylococcus aureus carriage by young Malaysian footballers during indoor training

Background: Research has shown that athletes are carrriers of Staphylococcus aureus during physical activity. Objective: To estimate the mean total plate count of S aureus carrried by footballers before and...

Membrane filter procedure for enumeration of Aeromonas hydrophila in fresh waters.

A membrane filter method (mA) for the enumeration of Aeromonas hydrophila in natural water samples was developed. The complex, primary medium employs trehalose as a fermentable carbohydrate and ampicillin and ethanol as selective inhibitors. After 20 h of incubation at 37 degrees C, an in situ mannitol fermentation test followed by an in situ oxidase test is used to further differentiate A. hydrophila from other aquatic and terrestrial microorganisms present in freshwaters. The primary medium decreases background microbial growth by about two orders of magnitude. The recoveries on mA medium from suspensions of A. hydrophila prepared from pure cultures and held for 24 h at 15 degrees C exceeded 95% of the recoveries on brain-heart infusion agar spread plates. The confirmation rate for colonies designated A. hydrophila was 98%, whereas 11% of the presumptively negative colonies were, in fact, A. hydrophila. Recoveries of A. hydrophila from fresh, surface water samples exceeded recoveries by the other methods examined.

Significance of urinary isolates of coagulase-negative Micrococcaceae

Of 16,347 urine cultures submitted to the hospital laboratory, 68 (0.4%) specimens from 50 patients yielded greater than 10(4) coagulase-negative staphylococci/ml in pure culture. A total of 62 of 63 organisms available for study were staphylococci: 45 Staphylococcus epidermidis (predominantly subgroup 1), 15 Staphylococcus saprophyticus (subgroup 3), and 2 Staphylococcus aureus. Twenty-one patients had "probable" urine infections. Eight patients had two or more positive urine cultures, and all isolates from the same patients were identical (by morphology, antibiotic susceptibility, and hemolytic pattern). Nine (75%) of the 12 isolates of S. saprophyticus, which were novobiocin resistant and nonhemolytic on the synergistic hemolysis test, were from patients with probable urinary infection. Eight were young women with acute symptoms and pyuria. Differences in the glucose and mannitol fermentation tests with different media may lead to difficulties in identification. Novobiocin resistance cannot be relied upon to differentiate isolates of S. saprophyticus from S. epidermidis.

A simple technique for the differentiation of Escherichia coli in water examination

New media for the demonstration of gas and indole production in a single tube were compared with media recommended by Report 71 for use in the 44°C confirmatory test for E. coli. The results demonstrate that the use of mannitol can reduce the numbers of false positive and false negative gas reactions. Indole-production tests may be performed in the same tube as the mannitol fermentation test by including tryptone in the medium. Tryptone mannitol ricinoleate broth and tryptone mannitol broth were found to be most suitable for the confirmation of E. coli in coliform presumptive tubes and membrane filter colonies respectively. The results of the mannitol fermentation and indole-production tests are available within 24 h at 44°C. The media are inexpensive and simple to prepare.

MANNITOL FERMENTATION AS AN INDICATOR OF CONJUNCTIVAL PATHOGENICITY OF STAPHYLOCOCCI

The recent reports of Burky, 1 Thygeson, 2 Allen 3 and O'Brien and Allen 4 indicate an increasing recognition of the important role of toxinproducing staphylococci in conjunctival and corneal inflammations. The common occurrence of saprophytic varieties of staphylococci on the margins of the lids and on the conjunctiva necessitates some test by which toxigenic strains may be recognized readily. Any strain can be tested for its ability to elaborate a conjunctivitis-producing toxin by a method which has been previously described, 2 but this is a time-consuming and expensive procedure and not adapted to routine use. Of the simple tests which have been shown to have some correlation with the production of toxin, the mannitol fermentation test appears to permit of widest application. Overnight readings can be obtained on phenol red—mannitol agar plates inoculated directly from the conjunctiva, a distinct advantage over the coagulase and crystal violet